Three position electric snap switch



Feb. 20, 1940. R. H. BENTLEY 2,191,364

THREE POSITION ELECTRIC SNAP SWITCH Filed Oct. 12, 1956 I I ZIII/d INSULATION INSULATION I INVENTOR ROBERT H. BENTLEY BY HIS ATTORNEYIS Patented F eb. 20, 1940.

UNITED STATES,

PATENT OFFICE Robert H. Bentley, Hartford, Conn, assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application October 12, 1936, Serial No. 105,341 11 Claims. (Cl. 200-6) This invention relates to electric snap switches. More particularly it relates to electric snap switches of the type in which the movable contact is capable of occupying more than two posi- 5 tions of rest. It is an object of this invention to improve and simplify the construction of switches of this type in order that they may be more quickly and less expensively manufactured Without sacrificing ruggedness of construction. Other 10 objects and advantages of my invention will become apparent as it is described in connection with the accompanying drawing.

In the drawing- Figure l isa side elevation view of an electric snap switch embodying the principles of my invention. In this'figure the switch is in midposition.

Figure 2 is a view similar to Figure 1 with the switch in the extreme right-hand position.

2 Figure 3 is a plan view of the invention shown in Figures 1 and 2.

Figure 4 is a longitudinal sectional view taken vertically through the operating mechanism alone and taken along line 4-4 of Figure 3.

2 Figure 5 is an end elevation view of the operating mechanism removed from the insulating base.

Figure 6 is a side elevation view of a modified form of operating mechanism falling within the 30 scope of my invention. In this figure the parts are shown in mid-position.

Figure 7 is a View similar to Figure 6 but with the parts in the extreme left-hand position.

Referring to the drawing, the movable switch 35 parts are mounted between a pair of parallel plates l and I2 which may be mounted upon a suitable insulating base. These plates together with the struts l3 which secure them together in spaced relation comprise the switch frame. Two pairs of contacts l4, l and I6, I! may be mounted on the insulating base, one pair being at each end in position to be bridged by a movable switch member or contact I8 as the switch is operated tobring the movable contact into its extreme right or left positions. The switch is operated by a handle or operating member 20 which is crescent-like in shape and is pivotally mounted by a pin 22 passing through one end portion, this pin being mounted transversely in the frame plates Ill and I2. Preferably this mounting pin 22 will be adjacent the bottom edges of the frame plates. An insulating handle 24 may be mounted upon the other end of this operating member and beneath the handle may be provided a hook formation 26 over which one end of a coiled tension spring 28 is looped, the other end of this spring being looped about the movable switch member it which extends transversely between and through the frame plates. This movable switch member may comprise a rod 5 of conducting material with cap-like enlargements or contact surfaces on its ends to engage with the stationary contact members l4 l5 and l6l1. To mount and guide the movable contact in its movement pairs of identical arms 30, 32 and 34, 36 are pivoted upon the inner and outer faces of each of the frame plates. Each of these arms has its own pivot. These pivots pass through the upper ends of the arms adjacent the upper edges of the frame plates and are axially spaced a small distance apart. The pivots 33, 31 of-the inside arms 32, 36 are coaxial, as are also the pivots 3|, 35 of the two arms 30, 34 on the outside faces of the frame plates. The lower ends of each of these arms are bifurcated by the longitudinally extending slots running from the lower ends of the arms up a short distance. Positioned in these slots and held therein is the movable contact member. The pivots of the arms are so related to the pivot of the operating lever 20 that when the operating lever is in mid-position (see Figs. 1 and 4) the line of action of the switch spring will be between the axes of the arm pivots and will pull the movable contact upwardly until it engages with the ends of the slots in the arms. Thus the arms and movable contact will be held at rest in mid-position. In this position the movable contact will not engage any fixed contacts in the embodiment of the invention illustrated. I 5

Since the stationary contacts are outside the switch frame and since the movable contact passes through the frame plates, identical raceways 40 are provided in the frame plates following the path of movement of the movable 40 contact. As may be seen in Figures 1, 2 and 4 the raceways have a scalloped form, being made up of intersecting arcs whose radii are the distance between the axes of pivot pins 3| and 33 and the axis of the movable contact when that contact is in the ends of the slots of the arms 30 and 32.

The ends of the raceways act as fixed stop means to limit the movement of the movable contact as it comes into its extreme positions.

It may now be seen that when the movable contact is in mid-position and the operatingv member of the switch is moved to the right the movable contact will remain stationary until the line of action of the switch spring has passed through the pivotal axis of the right (inside) set of arms 32, 36, after which the movable contact will snap into the extreme right position (see Figure 2) and will bridge the fixed contacts I6 and I1. Upon movement of the handle to the left from this extreme right-hand position the spring will be stressed until its line of action repasses through the pivotal axis of the inner arms after which the movable contact will snap into mid-position. Upon further movement of the operating handle to the left the spring will be stressed until its line of action passes from the pivotal axis of the left set (outer) arms 30, 34 and the movable contact will then snap into the extreme lefthand position.

In order to maintain the operating lever 20 in the mid-position the end of the operating member is extended beyond the pivotal mounting 22 thereof to engage with an indexing leaf-spring 42 which is secured to the frame plates across one end. The movement of the operating lever into its extreme positions is limited by its engagement with the struts I3.

In a modified form of operating mechanism the slots in the ends of the pivoted arms are closed providing movable stop means to limit the motion of the movable contact as it comes into its extreme or end positions, as may be seen from examination of Figs. 6 and 7. In these figures the arms I30, I32 are pivoted to the frame by pivot pins I3I and I33 in a manner similar to Figs. 1 and 5. Also the spring I28 is attached to the movable contact H8 and operating lever I20 in the same manner as in Figs. 1-5. However, the slots I30 and I32 in the arms I30, I32 are closed so that as the switch is moved into its extreme left-hand position and movable contact will engage the top of slot I30 and the bottom of slot I32 thus limiting the movement of the movable contact. The reverse will be true in the extreme right-hand position of the switch.

Obviously the switch may be mounted within a casing, if desired, and the fixed and movable contacts instead of having the form illustrated in the drawing may have any convenient form. Many other modifications within the scope of my invention will occur to those skilled in the art. Therefore I do not limit myself to the specific embodiments of the switch as described and illustrated.

I claim:

1. In an electric switch, fixed and movable contacts, mechanism for moving said movable contact through a succession of intersecting arcs comprising a plurality of pivoted members having spaced pivotal axes, an over-center spring, means constructed and arranged to move the line of action of said spring through the pivotal axes of said pivoted members, and a sliding connection between the swinging ends of said pivoted members.

2. In an electric switch, fixed and movable contacts, mechanism for moving said movable contact through a succession of intersecting arcs comprising a plurality of pivoted members having spaced pivotal axes, an over-center spring, means constructed and arranged to move the line of action of said spring through the pivotal axes of said pivoted members, and a sliding connection between the swinging ends of said pivoted members and fixed stop means to limit the movement of said pivoted members as they come into their extreme positions.

3. In an electric switch, fixed and movable contacts, mechanism for moving said movable contact through a succession of intersecting arcs comprising a plurality of pivoted members having spaced pivotal axes, an over-center spring, means constructed and arranged to move the line of action of said spring through the pivotal axes of said pivoted members, and a sliding-connection between the swinging ends of said pivoted members, and movable means to stop the movement of said pivoted members as they come into their extreme positions.

4. In an electric switch, fixed and movable contacts, mechanism movable into three positions of ber and said pin and slot connecting means to move said movable contact into its three positions with a snap.

5.In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and movable'contacts comprising a pair of arms, separate fixed. pivots.

having spaced axes for mounting said arms at one end, an operating meifiber, pivot means for said operating member equidistantly spaced from L said fixed pivots, pin and slot connecting means connecting the other ends of said arms, an overcenter spring connected to said operating member and said pin and slot connecting means to move said movable contact into its three positions with a snap, and fixed stop means to limit the movement of said arms as they come into their extreme positions.

6. In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and-movable contacts comprising a pair of arms, separate fixed pivots having spaced axes for mounting said arms at one end, an operating member, pivot means for said operating member equidistantly spaced from said fixed pivots, pin and slot connecting means connecting the other ends of said arms, an overcenter spring connected to said operating member and said pin'and slot connecting means to move said movable contact into its three positions with a snap, and movable means to stop the movement of said arms as they come into their extreme positions. I

'7. In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and movable contacts comprising operating means, a plurality of mov able means, separate fixed pivots having spaced axes for said movable means, a sliding connection between said movable means, an over-center spring actuated by said operating means and acting on said movable means to urge said movable means'each clockwise in one extreme position and each counter-clockwise in the other extreme position and to urge said movable means in opposite directions in the mid-position of the movable contact, the opposing forces of said movable members balancing each other in mid-position to hold said movable contact stationary.

8. In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and movable contacts comprising operating means, a plurality of movable means, separate fixed pivots having spaced axes for said movable means, a sliding connection between said movable means, an over-center spring actuated by said operating means and acting on said movable means to urge said movable means each clockwise in one extreme position and each counter-clockwise in the other extreme position and to urge said movable means in opposite directions in the mid-position of the movable contact, the opposing forces of said movable members balancing each other in mid-position to hold said movable contact stationary, and fixed stop 'means to limit the movement of said movable means as they come into their extreme positions.

9. In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and movable contacts comprising operating means, a plurality of movable means, separate fixed pivots having spaced axes for said movable means, a sliding connection between said movable means, an over-center spring actuated by said operating means and acting on said movable means to urge said movable means each clockwise in one extreme position and each counter-clockwise in the other extreme position and to urge said movable means in opposite directions in the mid-position of the movable contact, the opposing forces of said movable members balancing each other in midposition to hold said movable contact stationary, and movable stop means to limit the movement of said movable means as they come into their extreme positions.

10. In an electric switch, fixed and movable contacts, mechanism for moving said movable contact through a succession of intersecting arcs comprising a plurality of pivoted means having spaced axes and mounting said means at one end, means forming a sliding connection between the swinging ends oi' said pivoted means, energy storing means increasingly energized by initial movement of said operating means from one switch position toward another and acting after predetermined movement of said operating means to cause snap-acting movement of said movable contact from any one 01' said three positions of rest to another.

11. In an electric switch, fixed and movable contacts, mechanism movable into three positions of rest and causing engagement and disengagement of said fixed and movable contacts comprising operating means, a plurality of movable means, separate fixed pivots having spaced axes for said movable means, means forming a sliding connection between said movable means, energy storing means increasingly energized by initial movement of said operating means from one switch position toward another and acting on said movable means to urge said movable means each clockwise in one extreme position and each counter-clockwise in the other extreme position and to urge said movable means in opposite directions in the mid-position of the movable contact, the opposing forces of said movable members balancing each other in mid-position to hold said movable contact stationary.

ROBERT H. BENILEY. 

